The document proposes adding battery backup to femtocell devices to ensure continuous signal availability. Femtocells are small cellular base stations deployed by end users that provide improved indoor coverage, but their signals depend on the user's external power. To address this, the document suggests integrating a rechargeable battery into femtocells to power them for up to 14 hours during power outages. This would make femtocell signals continuously available to mobile users, overcoming their main disadvantage compared to traditional macro cell base stations.

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Mohan J N
MTech Student ( Networks and Internet Engineering )
Department of Electronics and Communication Engineering
Sri Jayachamarajendra College of Engineering
Mysuru ,India
mohanjn1709@gmail.com
Abstract—Mobile internet has become a basic necessity.
But due to interference in form of building and other entities the
reception of signals is interrupted in many areas. An optimal
solution for these is the small cells. These Small cells unlike the
Macro cells Base Stations can be placed even inside homes
providing better coverage and signal strength we called it as
Femto BSR.In this paper we are proposing to overcome the main
disadvantage of Femto BSR that is signal unavailability when
power down at end user point. Femto is a device which consumes
low power, low cost base station deployed by end user
point.Signal availability in BTS is 24*7 but in Femto which
depends on external power availability at user end. When power
loss at user end will turn off Femto device, this causes signal
unavailability to UEs (Mobiles). To overcome this we can
introduce inbuilt battery backup to Femto device.
Index Terms—Femto cells ,wireless network, Battery backup ,
Base Transceiver Station(BTS) , Signal Availability
I. INTRODUCTION
Base transceiver station (BTS) which proved wireless
communication between UE (Mobile) and network.BTS is
also called as Base station (BS) in 2G or Node B in 3G. Base
Station Control (BSC) act as concentrator. In this paper we are
not going to concentrate about GSM Architecture.
Figure 1 GSMNetworkArchitecture
Thyagaraja Murthy A
Associate Professor
Department of Electronics and Communication Engineering
Sri Jayachamarajendra College of Engineering
Mysuru ,India
trmsjce@gmail.com
II. WHY FEMTO CAME INTO PICTURE
The Base station having a number of radio frequency
channel called as Cells, so each cell covers limited area of
coverage generally 30 km region and limited number of UEs.
Due to interference in form of building and other entities the
reception of signals is interrupted in many areas. Base station
which is located near UEs have greater signal strength, but for
Base station which is located at extreme point of the coverage
area UEs have weak signal strength.UE consumes more
battery power when the signal is weak.
Figure 2 UE Connecting to Node B
In Figure 2 it is clear that when UE is too farfrom Base
station or Node-B (In 3G), UE should transmit the signal with
higher power which consumes more battery power.For
example is Figure 2, initially the UE sends the signal with
transmission power let's take X Watts, but Node-B is too far
from UE, so it's not possible for UE to connect with Node-B,
Now the UE will double its transmission let's take X*2 Watts
and try to connect.
This process of increasing the transmission power by UE
will be repeating until it reaches its maximum limit. If UE is
Approach of Femto Cell with Battery Backup
ISBN-13: 978-1537033419
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Proceedings of ICDER-2016
©IAETSD 201630

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still not able to connect Node-B, than it is clear that Node-B is
out of coverage area.
This problem is solved by Femto, Femtocells are low-power
wireless access points that operate in licensed spectrum to
establish a connection to standard UE to a mobile operator’s
network using residential DSL or cable broadband
connections.
The Femto Access Point (FAP) functions as the BTS and
the RNC. It is located at the End User’s Premises. So small,
infect that can be located in a customer’s Premises as shown in
Figure 3.The Femtocell unit generates a personal UE signal in
the home and communicates to the operator’s network using
standard broadband DSL on Cable service and it supports two
to five UE in a residential setting and area of coverage is
10metes. This will allow enhance coverage area and capacity
for each user within their residence.
III. ABOUT FEMTO
Third-generation cellular technology suffers from
insufficient indoor-signal penetration, leading to reduced
coverage in the environment where consumers spend two-
thirds of their period. Lowly coverage diminishes the
eminence of voice and video applications, and slows down
high-speed data services.
Figure3 Femto Architecture
To keep consumers gratified, 3G carriers have
improved capacity by building additional micro cell sites. This
strategy is pleasant much fewer striking. Site purchasing costs
are exorbitant and continue to mount as space on viable towers
and buildings fills up, landlord’s exact high rents and
regulators impose onerous permit requirements. Public
resistance to the building of extensive base stations is
increasingly common. Acquiring a site is only half the battle :
Erudite base station kit necessity then be purchased, installed
,insured ,operated and maintained.
Wellit's unblemished more customers want to use
mobile phones in the home, even when there’s a fixed line
available. Friends and family commonly dials a mobile UE
number first, and it’s where messages and contact lists are
stored. However, it is often the case that provides complete or
even sufficient mobile residential coverage is a significant
challenge for operators. From a competition perception, Femto
cells are essential because mobile operators need to seize
residential minutes from fixed suppliers, and reply to emergent
VoIP and Wi-Fi assistances.
Improving user experience in the home is also
necessary for decreasing churn and acquiring market share and
new revenues. However, high deployment costs ensure that 3G
networks infrequently outspread outside the regulatory
minimum.
Using Femto cells solves these problems with a
device that services power and backhaul via the consumer’s
present properties. It also enables capacity equivalent to a full
3G network area at very small transfer powers, dramatically
growing battery life of existing phones, without needing to
introduce Wi-Fi enabled handsets.
IV. ADVANTAGES OF FEMTO
 A Femtocell is used for compensating weak cellular
coverage inside the premises .
 Femtocell can also give lower call charges while the
caller calling from home, using the Femtocell as it
directly attaches to the core network over the internet.
 Some vendors are also planning to incorporate all the
3 types – Wi-Fi, DSL and cellular into the same box
to achieve maximum functionality.
 Voice calls/data calls over the Femtocells are
encrypts and the UE automatically switches over to
the Femtocells when they comes in their varieties –
eg. in home, where they are installed.
 Femtocell units can handle up to three or four
simultaneous calls, from the equivalent operators,
depends on the model. They can operate with normal
cellphones, without any enhancements.
 Femtocell entities can help's associated cellular
services like 3G by offering a better speed and data
rate when inside office block, where the coverage and
data rate is usually lesser than outside.
 Generally, the cell towers are back-hauled by
expending lines with bandwidth nearby 2 Mbps (in
some residences) and hence when newer services like
3G are introduced, these lines could not be enough
and hence may require a upgrade. But with
Femtocells, since the subscribers internet connection
are using, there could not be an problem with current
infrastructure if Femtocells are adopted in a large
scale.
 Femtocells can not simply spread the cellular macro
network but can also become the primary network if
enough Femtocells are implemented in an region. So,
all future demotions etc. can be done by the
Femtocells itself, reducing the number of macro base
stations needs to shield an area – however this is a
long shot, based on the current situation and the
problems described below.
Femto has this many advantages, but there is one
main drawback in femto system compared to Base transceiver
station is signal availability.
ISBN-13: 978-1537033419
www.iaetsd.in
Proceedings of ICDER-2016
©IAETSD 201631

3. 3
It means Base transceiver station available 24*7 to
UEs,in Femto which depends on external power availability at
user end.
V. APPROACH
To overcome signal unavailable to UEs when power
loss at femto side. We can design inbuilt battery to femto,
which makes femto available 24*7.
A. Ideal specification
Femto device required : 24V/0.5A=12 Watts
Ideal Battery
Battery unit : Ah/mAh
Battery power : V * Ah rating
Eg: 24V * 7Ah Battery gives power of 168 WattsFemto needs
12 Watts.
Battery backup is 168 / 12=14 hours.
By this approach we can make Femto 24*7 available to UEs.
VI. CONCLUSION
Femtocells have the potential to provide high-quality
network access to indoor users at low price, while
instantaneously decreasing the burden on the whole system.
This article has identified the key benefits of femtocells, the
technical and professional contests, and research
opportunities.
From a technical standpoint, providers look
experiments in provided that a low-cost answer while
providing inbuilt battery backup to femto. It makes femto
device more compatible and 24*7 signal available to end UEs.
VII. ACKNOWLEDGEMENT
I am extremely thankful to my guide Mr. Thyagaraja
Murthy A, Associate Professor, Dept. of ECE, SJCE, Mysuru
for their valuable guidance, constant assistance, provision,
fortitude and useful suggestions for the completion of this
work.
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ISBN-13: 978-1537033419
www.iaetsd.in
Proceedings of ICDER-2016
©IAETSD 201632